Art of producing articles by extrusion



Sept. 14 1926. Y

A. c. LUSHER riginal Fi led Feb. 2, 1922 Patented Sept. 14, 1926.

UNITED STATES ALBERT C. LUSHER, OF WATERBURY, CONNECTICUT, ASSIGNOR TOSCOVILL MANU- PATENT OFFICE.

FACTU'RING CO., OF WATERBURY, CONNECTICUT, A CORPORATION OF CONNEC-TICUT.

ART OF PRODUCING ARTICLES BY EXTRUSION.

Original application filed February 2, 1922, Serial No. 533.705. Dividedand. this application file November 30, 1923.

This invention relates to an improvement in the art of producingarticles by extrusion. The present application is a division from SerialNo. 533,705, filed February 2, 1922.

In producing tubesby extrusion with apparatus of the type including aram and a piercing-mandrel, it has been found that a considerable wasteof metal results from an uneven or deadend at the part of the produstfirst emerging from the die. Furthermore, in extruding tubes byapparatus of the type mentioned it has been found that the strains onthe piercing-mandrel during the piercing of-the slug or blank sometimesthrow the former out of alinement.

It is one of the principalobjects of the present invention to provide animproved method of producing tubular articles by extrusion such that thedead-end waste, or the greater part thereof, and the'tendency to-- warddisalinement of the piercing-mandrel, are avoided. r

lVith this general objectin view the 'invention consists in the methodwhich will first be described in connection with the accompanyingdrawing and then more partic ularly pointed out.

In the drawings:

Figs. 1 and 2 are sectional views of different forms of slugs;

Fig. 3 isa bottom plan view of the slugs shown in Figs. 1 and 2;

Fig. l is a conventional view'in cross section of an extrusion apparatusadapted to carry out part of the invention, and showing the slug of Fig.1 in position for extrusion;

Fig. 5 isa similar view showing the plunger in an advanced position withthe slu extruded into'the form of a tube;

F i 6 isa view similar to part of Fig. 151 a difierent form of slug inposition for extrusion;

Fig. 7 is. a transverse sectional view through the container chamberabove a slug of still different form;

Fig. 8 is a tczip plan view of a modified form of die; an v Fig. 9 is aperspective view of a rough blank br slug.

- In producing tubular articles according to the present invention, aslug or blank is subjected to the action of a piercing-mandrel and aram. The drawings show, more or Serial No. 677,662.

less conventionally, apparatus capable of so forming tubes. ReferringtoFigs. el and ,5,

in the apparatus shown as an example, a

tom of the chamber 21 is a die 23 having a round die opening 24 of theform shown. The slug is acted upon by a plunger comprising, as hereshown, a ram 25 which substantially fits the chamber 21 and apiercing-mandrel 26'of smaller diameter, this plunger being reciprocatedby a suitable press mechanism (not shown). As the plunger is movedagainst the slug, the piercing-mandrel first pierces the slug. By thetime ram 25 engages the slug, the piercingmandrel extends into the dieopening and acts as a mandrel. Since the only escape for the metal isbetween the die and mandrel, the pressure of the ram extrudes the sluginto the form of a tube 27. If desired, the

plunger may be stopped at the proper time.

to leave a portion of the slug unextruded, thus leaving on the tube ahead 28. It will be understood that the outer and inner diameters of theextruded tube depend" on the dimensions of the die opening and mandrelrespectively To prevent the waste resulting from uneven, dead, endsabove. mentioned, the slug may be of a-character to obviate prematureflow of metal through the die opening upon initial pressure of theplunger. This may be accomplished by using a slug having a cavity ordepression in the face toward the die opening. .This depression may beconveniently formed ,by upsetting the metal of a rough blank, such, forexample, as shown in Fig. 9, by means of suitable punches. This roughblank is a solid, round slug having flat faces and may be formedby-casting, cut-. ting from rod stock, or the like. Figs. 1 and 2illustrate two forms of slugs ready to be extruded. Fig. 1 shows a slug.30 formed from the rough blank of Fig. 9 by upsetting the metal toprovidea. cavity or depression 31 in one face. Fig. 2 shows a slug32'hav- 'ing a similar cavity in both faces/ With slugs having thisdouble cavity, the face toward the die opening will always have a cavityregardless of how the slugs are fed to the chamber.

With a slug, such as either ofth ose described, confined in the chamber21 (Fig. 4),

upon initial pressure of the piercing-mandrelthe initial flow of metalis such asto tend to fill up the cavity 31, rather than a premature flowthrough the die opening. Thereafter, the piercing of the slug and theextrusion of the tube proceed as above described. As a result, theextruded tube is sulistantially devoid of an uneven or dead en Incarrying out the invention in its entirety, a s ug is used that isadapted to permit a radial flow, of metal toward the wall of thechamber. This may be accomplished by using a round slug 33 that issubstantially smaller in diameter than the chamber 21 of 1 the press(Fig. 6). Or the slug may have a transverse cross section that isnon-circular. A convenient form; of slug is one that is substantially acube or other parallelopipedon such a slug beingshown at 34in Fig. 7. Ifdesired, the slug may have its edges slightly rounded. This slug may beformed in any suitable manner as by casting or cutting from rod stock.It may advantageously have the facial cavity already described as mayalso the slug 33. When a small sized round slug or a slug ofnon-circular transverse cross section is subjected to the pressure ofthe extrusion plunger, there is an initial radial flow of metal towardthe wall of the chamber. This initial radial flow relieves, to a greatextent, the strain on the piercingmandrel during its piercing operationand so tends to prevent dlsalinement thereof. By lSlIlg a slugsubstantially. square in cross section with its dia onals only enoughshorter than the cham r diameter to permit proper insertion, the slug isself-centermg when fed to the chamber. Furthermore,

\ this form of slug is an" advantageous means my hand.

between maximum cross-sectional area and maximum flow-receivin space.

Certain tubular articles such, for example, as the tire valve casingsdescribed in the above mentioned parent application, have two -flatsides. These may be formed by ex trading the tubes to shape. This may beaccomplished by extruding the slug through a die opening such asillustrated in Fig. 8. As there shown, a die 35 has a die'opening 36-defined by. two parallel straight lines 37 and two opposing curved lines38 which are preferably arcs of circles. With the die 35 substituted inthe press for die 23, the extruded tube has two flat sides.

What I claim is:

ing tubular articles which comprises confining, in a chamber having adie open1ng, 'a slug having a cavity in the face toward sald dieopening, and subjecting "the slug to the action of a piercing-mandreland a ram.

2. The herein described method of produc- 1. The herein described methodof producing tubular articles which comprises formhaving a die opening,with one of said faces toward the opening, and subjecting the slug totheaction of a piercing-mandrel and a so ram.

In testimony whereof, I have hereunto set ALBERT c. LUSHER'

